The Cigar Oasis Electronic Humidifier Refill Water Cartridge with Battery Pack fits both the Cigar Oasis and Cigar Oasis XL units. Each cartridge contains a foam core element combined with distilled water and an antifungal agent for optimal cigar preservation. This unit is the same cartridge as the short refill cartridge but includes a battery pack that clips on and attaches to the electronic Oasis control unit. The battery operation enables the Cigar Oasis to run without the need of an AC outlet. Need to take your humidor in your vehicle, on a boat, etc? The new Cigar Oasis Water Cartridge with Battery Pack is the perfect solution.